1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ARCH_POWERPC_UACCESS_H 3 #define _ARCH_POWERPC_UACCESS_H 4 5 #include <linux/sizes.h> 6 7 #include <asm/processor.h> 8 #include <asm/page.h> 9 #include <asm/extable.h> 10 #include <asm/kup.h> 11 #include <asm/asm-compat.h> 12 13 #ifdef __powerpc64__ 14 /* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */ 15 #define TASK_SIZE_MAX TASK_SIZE_USER64 16 #endif 17 18 /* Threshold above which VMX copy path is used */ 19 #define VMX_COPY_THRESHOLD 3328 20 21 #include <asm-generic/access_ok.h> 22 23 /* 24 * These are the main single-value transfer routines. They automatically 25 * use the right size if we just have the right pointer type. 26 * 27 * This gets kind of ugly. We want to return _two_ values in "get_user()" 28 * and yet we don't want to do any pointers, because that is too much 29 * of a performance impact. Thus we have a few rather ugly macros here, 30 * and hide all the ugliness from the user. 31 * 32 * The "__xxx" versions of the user access functions are versions that 33 * do not verify the address space, that must have been done previously 34 * with a separate "access_ok()" call (this is used when we do multiple 35 * accesses to the same area of user memory). 36 * 37 * As we use the same address space for kernel and user data on the 38 * PowerPC, we can just do these as direct assignments. (Of course, the 39 * exception handling means that it's no longer "just"...) 40 * 41 */ 42 #define __put_user(x, ptr) \ 43 ({ \ 44 long __pu_err; \ 45 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \ 46 __typeof__(*(ptr)) __pu_val = (__typeof__(*(ptr)))(x); \ 47 __typeof__(sizeof(*(ptr))) __pu_size = sizeof(*(ptr)); \ 48 \ 49 might_fault(); \ 50 do { \ 51 __label__ __pu_failed; \ 52 \ 53 allow_user_access(__pu_addr, KUAP_WRITE); \ 54 __put_user_size_goto(__pu_val, __pu_addr, __pu_size, __pu_failed); \ 55 prevent_user_access(KUAP_WRITE); \ 56 __pu_err = 0; \ 57 break; \ 58 \ 59 __pu_failed: \ 60 prevent_user_access(KUAP_WRITE); \ 61 __pu_err = -EFAULT; \ 62 } while (0); \ 63 \ 64 __pu_err; \ 65 }) 66 67 #define put_user(x, ptr) \ 68 ({ \ 69 __typeof__(*(ptr)) __user *_pu_addr = (ptr); \ 70 \ 71 access_ok(_pu_addr, sizeof(*(ptr))) ? \ 72 __put_user(x, _pu_addr) : -EFAULT; \ 73 }) 74 75 /* 76 * We don't tell gcc that we are accessing memory, but this is OK 77 * because we do not write to any memory gcc knows about, so there 78 * are no aliasing issues. 79 */ 80 /* -mprefixed can generate offsets beyond range, fall back hack */ 81 #ifdef CONFIG_PPC_KERNEL_PREFIXED 82 #define __put_user_asm_goto(x, addr, label, op) \ 83 asm goto( \ 84 "1: " op " %0,0(%1) # put_user\n" \ 85 EX_TABLE(1b, %l2) \ 86 : \ 87 : "r" (x), "b" (addr) \ 88 : \ 89 : label) 90 #else 91 #define __put_user_asm_goto(x, addr, label, op) \ 92 asm goto( \ 93 "1: " op "%U1%X1 %0,%1 # put_user\n" \ 94 EX_TABLE(1b, %l2) \ 95 : \ 96 : "r" (x), "m<>" (*addr) \ 97 : \ 98 : label) 99 #endif 100 101 #ifdef __powerpc64__ 102 #ifdef CONFIG_PPC_KERNEL_PREFIXED 103 #define __put_user_asm2_goto(x, ptr, label) \ 104 __put_user_asm_goto(x, ptr, label, "std") 105 #else 106 #define __put_user_asm2_goto(x, addr, label) \ 107 asm goto ("1: std%U1%X1 %0,%1 # put_user\n" \ 108 EX_TABLE(1b, %l2) \ 109 : \ 110 : "r" (x), DS_FORM_CONSTRAINT (*addr) \ 111 : \ 112 : label) 113 #endif // CONFIG_PPC_KERNEL_PREFIXED 114 #else /* __powerpc64__ */ 115 #define __put_user_asm2_goto(x, addr, label) \ 116 asm goto( \ 117 "1: stw%X1 %0, %1\n" \ 118 "2: stw%X1 %L0, %L1\n" \ 119 EX_TABLE(1b, %l2) \ 120 EX_TABLE(2b, %l2) \ 121 : \ 122 : "r" (x), "m" (*addr) \ 123 : \ 124 : label) 125 #endif /* __powerpc64__ */ 126 127 #define __put_user_size_goto(x, ptr, size, label) \ 128 do { \ 129 __typeof__(*(ptr)) __user *__pus_addr = (ptr); \ 130 \ 131 switch (size) { \ 132 case 1: __put_user_asm_goto(x, __pus_addr, label, "stb"); break; \ 133 case 2: __put_user_asm_goto(x, __pus_addr, label, "sth"); break; \ 134 case 4: __put_user_asm_goto(x, __pus_addr, label, "stw"); break; \ 135 case 8: __put_user_asm2_goto(x, __pus_addr, label); break; \ 136 default: BUILD_BUG(); \ 137 } \ 138 } while (0) 139 140 /* 141 * This does an atomic 128 byte aligned load from userspace. 142 * Upto caller to do enable_kernel_vmx() before calling! 143 */ 144 #define __get_user_atomic_128_aligned(kaddr, uaddr, err) \ 145 __asm__ __volatile__( \ 146 ".machine push\n" \ 147 ".machine altivec\n" \ 148 "1: lvx 0,0,%1 # get user\n" \ 149 " stvx 0,0,%2 # put kernel\n" \ 150 ".machine pop\n" \ 151 "2:\n" \ 152 ".section .fixup,\"ax\"\n" \ 153 "3: li %0,%3\n" \ 154 " b 2b\n" \ 155 ".previous\n" \ 156 EX_TABLE(1b, 3b) \ 157 : "=r" (err) \ 158 : "b" (uaddr), "b" (kaddr), "i" (-EFAULT), "0" (err)) 159 160 #ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT 161 162 /* -mprefixed can generate offsets beyond range, fall back hack */ 163 #ifdef CONFIG_PPC_KERNEL_PREFIXED 164 #define __get_user_asm_goto(x, addr, label, op) \ 165 asm_goto_output( \ 166 "1: "op" %0,0(%1) # get_user\n" \ 167 EX_TABLE(1b, %l2) \ 168 : "=r" (x) \ 169 : "b" (addr) \ 170 : \ 171 : label) 172 #else 173 #define __get_user_asm_goto(x, addr, label, op) \ 174 asm_goto_output( \ 175 "1: "op"%U1%X1 %0, %1 # get_user\n" \ 176 EX_TABLE(1b, %l2) \ 177 : "=r" (x) \ 178 : "m<>" (*addr) \ 179 : \ 180 : label) 181 #endif 182 183 #ifdef __powerpc64__ 184 #ifdef CONFIG_PPC_KERNEL_PREFIXED 185 #define __get_user_asm2_goto(x, addr, label) \ 186 __get_user_asm_goto(x, addr, label, "ld") 187 #else 188 #define __get_user_asm2_goto(x, addr, label) \ 189 asm_goto_output( \ 190 "1: ld%U1%X1 %0, %1 # get_user\n" \ 191 EX_TABLE(1b, %l2) \ 192 : "=r" (x) \ 193 : DS_FORM_CONSTRAINT (*addr) \ 194 : \ 195 : label) 196 #endif // CONFIG_PPC_KERNEL_PREFIXED 197 #else /* __powerpc64__ */ 198 #define __get_user_asm2_goto(x, addr, label) \ 199 asm_goto_output( \ 200 "1: lwz%X1 %0, %1\n" \ 201 "2: lwz%X1 %L0, %L1\n" \ 202 EX_TABLE(1b, %l2) \ 203 EX_TABLE(2b, %l2) \ 204 : "=&r" (x) \ 205 : "m" (*addr) \ 206 : \ 207 : label) 208 #endif /* __powerpc64__ */ 209 210 #define __get_user_size_goto(x, ptr, size, label) \ 211 do { \ 212 BUILD_BUG_ON(size > sizeof(x)); \ 213 switch (size) { \ 214 case 1: __get_user_asm_goto(x, (u8 __user *)ptr, label, "lbz"); break; \ 215 case 2: __get_user_asm_goto(x, (u16 __user *)ptr, label, "lhz"); break; \ 216 case 4: __get_user_asm_goto(x, (u32 __user *)ptr, label, "lwz"); break; \ 217 case 8: __get_user_asm2_goto(x, (u64 __user *)ptr, label); break; \ 218 default: x = 0; BUILD_BUG(); \ 219 } \ 220 } while (0) 221 222 #define __get_user_size_allowed(x, ptr, size, retval) \ 223 do { \ 224 __label__ __gus_failed; \ 225 \ 226 __get_user_size_goto(x, ptr, size, __gus_failed); \ 227 retval = 0; \ 228 break; \ 229 __gus_failed: \ 230 x = 0; \ 231 retval = -EFAULT; \ 232 } while (0) 233 234 #else /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT */ 235 236 #define __get_user_asm(x, addr, err, op) \ 237 __asm__ __volatile__( \ 238 "1: "op"%U2%X2 %1, %2 # get_user\n" \ 239 "2:\n" \ 240 ".section .fixup,\"ax\"\n" \ 241 "3: li %0,%3\n" \ 242 " li %1,0\n" \ 243 " b 2b\n" \ 244 ".previous\n" \ 245 EX_TABLE(1b, 3b) \ 246 : "=r" (err), "=r" (x) \ 247 : "m<>" (*addr), "i" (-EFAULT), "0" (err)) 248 249 #ifdef __powerpc64__ 250 #define __get_user_asm2(x, addr, err) \ 251 __get_user_asm(x, addr, err, "ld") 252 #else /* __powerpc64__ */ 253 #define __get_user_asm2(x, addr, err) \ 254 __asm__ __volatile__( \ 255 "1: lwz%X2 %1, %2\n" \ 256 "2: lwz%X2 %L1, %L2\n" \ 257 "3:\n" \ 258 ".section .fixup,\"ax\"\n" \ 259 "4: li %0,%3\n" \ 260 " li %1,0\n" \ 261 " li %L1,0\n" \ 262 " b 3b\n" \ 263 ".previous\n" \ 264 EX_TABLE(1b, 4b) \ 265 EX_TABLE(2b, 4b) \ 266 : "=r" (err), "=&r" (x) \ 267 : "m" (*addr), "i" (-EFAULT), "0" (err)) 268 #endif /* __powerpc64__ */ 269 270 #define __get_user_size_allowed(x, ptr, size, retval) \ 271 do { \ 272 retval = 0; \ 273 BUILD_BUG_ON(size > sizeof(x)); \ 274 switch (size) { \ 275 case 1: __get_user_asm(x, (u8 __user *)ptr, retval, "lbz"); break; \ 276 case 2: __get_user_asm(x, (u16 __user *)ptr, retval, "lhz"); break; \ 277 case 4: __get_user_asm(x, (u32 __user *)ptr, retval, "lwz"); break; \ 278 case 8: __get_user_asm2(x, (u64 __user *)ptr, retval); break; \ 279 default: x = 0; BUILD_BUG(); \ 280 } \ 281 } while (0) 282 283 #define __get_user_size_goto(x, ptr, size, label) \ 284 do { \ 285 long __gus_retval; \ 286 \ 287 __get_user_size_allowed(x, ptr, size, __gus_retval); \ 288 if (__gus_retval) \ 289 goto label; \ 290 } while (0) 291 292 #endif /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT */ 293 294 /* 295 * This is a type: either unsigned long, if the argument fits into 296 * that type, or otherwise unsigned long long. 297 */ 298 #define __long_type(x) \ 299 __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL)) 300 301 #define __get_user(x, ptr) \ 302 ({ \ 303 long __gu_err; \ 304 __long_type(*(ptr)) __gu_val; \ 305 __typeof__(*(ptr)) __user *__gu_addr = (ptr); \ 306 __typeof__(sizeof(*(ptr))) __gu_size = sizeof(*(ptr)); \ 307 \ 308 might_fault(); \ 309 barrier_nospec(); \ 310 allow_user_access(NULL, KUAP_READ); \ 311 __get_user_size_allowed(__gu_val, __gu_addr, __gu_size, __gu_err); \ 312 prevent_user_access(KUAP_READ); \ 313 (x) = (__typeof__(*(ptr)))__gu_val; \ 314 \ 315 __gu_err; \ 316 }) 317 318 #define get_user(x, ptr) \ 319 ({ \ 320 __typeof__(*(ptr)) __user *_gu_addr = (ptr); \ 321 \ 322 access_ok(_gu_addr, sizeof(*(ptr))) ? \ 323 __get_user(x, _gu_addr) : \ 324 ((x) = (__force __typeof__(*(ptr)))0, -EFAULT); \ 325 }) 326 327 /* more complex routines */ 328 329 extern unsigned long __copy_tofrom_user(void __user *to, 330 const void __user *from, unsigned long size); 331 332 unsigned long __copy_tofrom_user_base(void __user *to, 333 const void __user *from, unsigned long size); 334 335 unsigned long __copy_tofrom_user_power7_vmx(void __user *to, 336 const void __user *from, unsigned long size); 337 338 static __always_inline bool will_use_vmx(unsigned long n) 339 { 340 return IS_ENABLED(CONFIG_ALTIVEC) && cpu_has_feature(CPU_FTR_VMX_COPY) && 341 n > VMX_COPY_THRESHOLD; 342 } 343 344 static __always_inline unsigned long 345 raw_copy_tofrom_user(void __user *to, const void __user *from, 346 unsigned long n, unsigned long dir) 347 { 348 unsigned long ret; 349 350 if (will_use_vmx(n) && enter_vmx_usercopy()) { 351 allow_user_access(to, dir); 352 ret = __copy_tofrom_user_power7_vmx(to, from, n); 353 prevent_user_access(dir); 354 exit_vmx_usercopy(); 355 356 if (unlikely(ret)) { 357 allow_user_access(to, dir); 358 ret = __copy_tofrom_user_base(to, from, n); 359 prevent_user_access(dir); 360 } 361 return ret; 362 } 363 364 allow_user_access(to, dir); 365 ret = __copy_tofrom_user(to, from, n); 366 prevent_user_access(dir); 367 return ret; 368 } 369 370 #ifdef CONFIG_PPC64 371 static inline unsigned long 372 raw_copy_in_user(void __user *to, const void __user *from, unsigned long n) 373 { 374 barrier_nospec(); 375 return raw_copy_tofrom_user(to, from, n, KUAP_READ_WRITE); 376 } 377 #endif /* CONFIG_PPC64 */ 378 379 static inline unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n) 380 { 381 return raw_copy_tofrom_user((__force void __user *)to, from, n, KUAP_READ); 382 } 383 384 static inline unsigned long 385 raw_copy_to_user(void __user *to, const void *from, unsigned long n) 386 { 387 return raw_copy_tofrom_user(to, (__force const void __user *)from, n, KUAP_WRITE); 388 } 389 390 unsigned long __arch_clear_user(void __user *addr, unsigned long size); 391 392 static inline unsigned long __clear_user(void __user *addr, unsigned long size) 393 { 394 unsigned long ret; 395 396 might_fault(); 397 allow_user_access(addr, KUAP_WRITE); 398 ret = __arch_clear_user(addr, size); 399 prevent_user_access(KUAP_WRITE); 400 return ret; 401 } 402 403 static inline unsigned long clear_user(void __user *addr, unsigned long size) 404 { 405 return likely(access_ok(addr, size)) ? __clear_user(addr, size) : size; 406 } 407 408 extern long strncpy_from_user(char *dst, const char __user *src, long count); 409 extern __must_check long strnlen_user(const char __user *str, long n); 410 411 #ifdef CONFIG_ARCH_HAS_COPY_MC 412 unsigned long __must_check 413 copy_mc_generic(void *to, const void *from, unsigned long size); 414 415 static inline unsigned long __must_check 416 copy_mc_to_kernel(void *to, const void *from, unsigned long size) 417 { 418 return copy_mc_generic(to, from, size); 419 } 420 #define copy_mc_to_kernel copy_mc_to_kernel 421 422 static inline unsigned long __must_check 423 copy_mc_to_user(void __user *to, const void *from, unsigned long n) 424 { 425 if (check_copy_size(from, n, true)) { 426 if (access_ok(to, n)) { 427 allow_user_access(to, KUAP_WRITE); 428 n = copy_mc_generic((void __force *)to, from, n); 429 prevent_user_access(KUAP_WRITE); 430 } 431 } 432 433 return n; 434 } 435 #endif 436 437 extern size_t copy_from_user_flushcache(void *dst, const void __user *src, size_t size); 438 439 static __must_check __always_inline bool __user_access_begin(const void __user *ptr, size_t len, 440 unsigned long dir) 441 { 442 if (unlikely(!access_ok(ptr, len))) 443 return false; 444 445 might_fault(); 446 447 if (dir & KUAP_READ) 448 barrier_nospec(); 449 allow_user_access((void __user *)ptr, dir); 450 return true; 451 } 452 453 #define user_access_begin(p, l) __user_access_begin(p, l, KUAP_READ_WRITE) 454 #define user_read_access_begin(p, l) __user_access_begin(p, l, KUAP_READ) 455 #define user_write_access_begin(p, l) __user_access_begin(p, l, KUAP_WRITE) 456 457 #define user_access_end() prevent_user_access(KUAP_READ_WRITE) 458 #define user_read_access_end() prevent_user_access(KUAP_READ) 459 #define user_write_access_end() prevent_user_access(KUAP_WRITE) 460 461 #define user_access_save prevent_user_access_return 462 #define user_access_restore restore_user_access 463 464 /* 465 * Masking the user address is an alternative to a conditional 466 * user_access_begin that can avoid the fencing. This only works 467 * for dense accesses starting at the address. 468 */ 469 static inline void __user *mask_user_address_simple(const void __user *ptr) 470 { 471 unsigned long addr = (unsigned long)ptr; 472 unsigned long mask = (unsigned long)(((long)addr >> (BITS_PER_LONG - 1)) & LONG_MAX); 473 474 return (void __user *)(addr & ~mask); 475 } 476 477 static inline void __user *mask_user_address_isel(const void __user *ptr) 478 { 479 unsigned long addr; 480 481 asm("cmplw %1, %2; iselgt %0, %2, %1" : "=r"(addr) : "r"(ptr), "r"(TASK_SIZE) : "cr0"); 482 483 return (void __user *)addr; 484 } 485 486 /* TASK_SIZE is a multiple of 128K for shifting by 17 to the right */ 487 static inline void __user *mask_user_address_32(const void __user *ptr) 488 { 489 unsigned long addr = (unsigned long)ptr; 490 unsigned long mask = (unsigned long)((long)((TASK_SIZE >> 17) - 1 - (addr >> 17)) >> 31); 491 492 addr = (addr & ~mask) | (TASK_SIZE & mask); 493 494 return (void __user *)addr; 495 } 496 497 static inline void __user *mask_user_address_fallback(const void __user *ptr) 498 { 499 unsigned long addr = (unsigned long)ptr; 500 501 return (void __user *)(likely(addr < TASK_SIZE) ? addr : TASK_SIZE); 502 } 503 504 static inline void __user *mask_user_address(const void __user *ptr) 505 { 506 #ifdef MODULES_VADDR 507 const unsigned long border = MODULES_VADDR; 508 #else 509 const unsigned long border = PAGE_OFFSET; 510 #endif 511 512 if (IS_ENABLED(CONFIG_PPC64)) 513 return mask_user_address_simple(ptr); 514 if (IS_ENABLED(CONFIG_E500)) 515 return mask_user_address_isel(ptr); 516 if (TASK_SIZE <= UL(SZ_2G) && border >= UL(SZ_2G)) 517 return mask_user_address_simple(ptr); 518 if (IS_ENABLED(CONFIG_PPC_BARRIER_NOSPEC)) 519 return mask_user_address_32(ptr); 520 return mask_user_address_fallback(ptr); 521 } 522 523 static __always_inline void __user *__masked_user_access_begin(const void __user *p, 524 unsigned long dir) 525 { 526 void __user *ptr = mask_user_address(p); 527 528 might_fault(); 529 allow_user_access(ptr, dir); 530 531 return ptr; 532 } 533 534 #define masked_user_access_begin(p) __masked_user_access_begin(p, KUAP_READ_WRITE) 535 #define masked_user_read_access_begin(p) __masked_user_access_begin(p, KUAP_READ) 536 #define masked_user_write_access_begin(p) __masked_user_access_begin(p, KUAP_WRITE) 537 538 #define arch_unsafe_get_user(x, p, e) do { \ 539 __long_type(*(p)) __gu_val; \ 540 __typeof__(*(p)) __user *__gu_addr = (p); \ 541 \ 542 __get_user_size_goto(__gu_val, __gu_addr, sizeof(*(p)), e); \ 543 (x) = (__typeof__(*(p)))__gu_val; \ 544 } while (0) 545 546 #define arch_unsafe_put_user(x, p, e) \ 547 __put_user_size_goto((__typeof__(*(p)))(x), (p), sizeof(*(p)), e) 548 549 #define unsafe_copy_from_user(d, s, l, e) \ 550 do { \ 551 u8 *_dst = (u8 *)(d); \ 552 const u8 __user *_src = (const u8 __user *)(s); \ 553 size_t _len = (l); \ 554 int _i; \ 555 \ 556 for (_i = 0; _i < (_len & ~(sizeof(u64) - 1)); _i += sizeof(u64)) \ 557 unsafe_get_user(*(u64 *)(_dst + _i), (u64 __user *)(_src + _i), e); \ 558 if (_len & 4) { \ 559 unsafe_get_user(*(u32 *)(_dst + _i), (u32 __user *)(_src + _i), e); \ 560 _i += 4; \ 561 } \ 562 if (_len & 2) { \ 563 unsafe_get_user(*(u16 *)(_dst + _i), (u16 __user *)(_src + _i), e); \ 564 _i += 2; \ 565 } \ 566 if (_len & 1) \ 567 unsafe_get_user(*(u8 *)(_dst + _i), (u8 __user *)(_src + _i), e); \ 568 } while (0) 569 570 #define unsafe_copy_to_user(d, s, l, e) \ 571 do { \ 572 u8 __user *_dst = (u8 __user *)(d); \ 573 const u8 *_src = (const u8 *)(s); \ 574 size_t _len = (l); \ 575 int _i; \ 576 \ 577 for (_i = 0; _i < (_len & ~(sizeof(u64) - 1)); _i += sizeof(u64)) \ 578 unsafe_put_user(*(u64 *)(_src + _i), (u64 __user *)(_dst + _i), e); \ 579 if (_len & 4) { \ 580 unsafe_put_user(*(u32*)(_src + _i), (u32 __user *)(_dst + _i), e); \ 581 _i += 4; \ 582 } \ 583 if (_len & 2) { \ 584 unsafe_put_user(*(u16*)(_src + _i), (u16 __user *)(_dst + _i), e); \ 585 _i += 2; \ 586 } \ 587 if (_len & 1) \ 588 unsafe_put_user(*(u8*)(_src + _i), (u8 __user *)(_dst + _i), e); \ 589 } while (0) 590 591 #define arch_get_kernel_nofault(dst, src, type, err_label) \ 592 __get_user_size_goto(*((type *)(dst)), \ 593 (__force type __user *)(src), sizeof(type), err_label) 594 595 #define arch_put_kernel_nofault(dst, src, type, err_label) \ 596 __put_user_size_goto(*((type *)(src)), \ 597 (__force type __user *)(dst), sizeof(type), err_label) 598 599 #endif /* _ARCH_POWERPC_UACCESS_H */ 600